This is a great article. 3D annotation is the way of the future, with better and better capabilities in the CAD tools. It is nice to see that experts in the application are now available, so more companies should be moving this way. 2D drawings were OK in the 1900's, but are a little too primitive for this century. I can't find a college grad that can read one.

CPerhala(Unregistered)08/08/06 07:00 AM

Increase Solid Model Value with 3D GD&T

Article provides a good overview of data needed to manage a product's dimensions over the life cycle. The comments about datum identification and multiple references in numerous drawings is dead on accurate; this has been the root of many headaches.The focus on UGS systems only limits the usefulness of the article and can give the impression of an extended advertisement. It would be of interest to know of other packages that can do the same or similar things.Some of the grammar should be cleaned up to make it more readable. There are several instances of the wrong word being used (e.g., 'to' instead of 'too') which requires rereading the sentance (sometimes several times) to understand the thought being conveyed.On the balance, a useful article. Some additional work would make it more readable (and useful).

Thank you for your honest feedback. As for other systems that can also emulate this process, there are none. However, bringing different packages together from various third parties may at least approach the process.

The good news is that more systems are at least providing 3D GD&T and companies like Adobe are chiming in with providing extended viewer capability to provide downstream value in the 3D GD&T without having to use CAD.

But when it comes to tolerance analysis, I think 3D is the only way to go and from what I have seen, VisVSA is simply in the lead.

I also appreciate your candor with regard to my writing style. I can't please everyone and you are right I did find an instance of "to" being incorrectly used. Sorry about that. Btw- sentance is spelled sentence. lol and again thanks!

Joe(Unregistered)08/19/06 08:30 AM

INSPECTION

I was assigned a job of making some inspection drawings from some aircraft parts. The models were done in UG and came with drawings with critical dimensions and GD&T. I was using KEYCREATOR (CADKEY) to create the drawings. These parts were designed by CAD jockeys or engineers. If they had to make a complete drawing they would have realized the problems that manufacturing would face with making and inspecting these parts. The article shows a block with a couple of holes in it. Many parts have hundreds of features that have to be defined and inspected. You either do it by sitting down at a computer and verifying that the part matches the model feature by feature or you create a hard copy drawing that anyone can pull out at any time to check a feature. Now many companies are sending out models with minimum annotation. But they are just passing this required function off to the manufacturing company to do the full inspection drawing. This is something that would be much better done by the original design group. Complete drawings are part of the design function.

With regard to inspection and limited dimension drawings, rest assured I feel your pain. I do not support limited dimensioning any more then I support limited 2D tolerance analysis. Please re-read the third to last paragraph. Please not there and on my process map, that there are products for the inspection process that take adavantage of the 3D annotation. The UG-AIMS product is very exciting.
As for anyone can pull a fully detailed drawing anytime and read it, well the flaw has always been that a fully detailed drawing is normally not detailed correctly, its cluttered and hard to read by someone versed in GD&T and detail views and all that much less for someone who isn't.
I know my block example only has a few holes, but if you had a chance to look at how "model views" manage the annotation on a complex part, I think you would be pleasantly suprised. Plus, with a 3D part/assy, it is much easier to "see" the design and "manage" it. For example, drawings pulled from a drawer are often out of date. Ever experience that issue? Or, the drawing is up to date but the CAD model isn't. And is much of the manufacturing process driven by the CAD model?
Trust me. We are in agreement. Detailing of features needs to be complete. Please do not misunderstand the efficiency of leaving off BASIC dimensions and multiple copies of datum symbols as a support for limited part/product definition.
However, I do support title block tolerancing for robust designs that do not require excessive detailed and unique GD&T on every feature. To bring my point home, on my "simple" block, a linear overall width dimension is not necessary with a simple profile of surface control. In fact, a "feature of size" linear dimension intended to control the width of the "simple" block would in fact be incorrect and an extremely poor transfer of functional design intent.
Finally, I am a huge advocate for CMM and especially non-contact lazer point cloud inspection tools and process to further take advantage of the not so new relm of 3D annotation and "smart modeling".
I am only to glad to help. My contact information is at the bottom of the article.

Reading a drawing is a requirement for engineers and is the skill of a drafter. I personally have created hundreds maybe thousands of clear concise complex drawings from which parts have been made. We didn't have 3D solid models to work with. We had complex installation drawings made from full scale layouts of aircraft structure, mechanical and kinematic assemblies. We had to define 3D parts in 2D. This article made me realize that many out there have never defined a 3D part in a 2D drawing and never will. I am going to write an article for my customers (I have been selling CADKEY for over 21 years, and a Design Drafter for gulp!! 40 years) about the history of the drawing. One more point: Engineers rarely made drawings, but they seem now to be put to work creating 3D models, which I consider is a total waste of his skills. Boeing had 5 or more drafters under one engineer.

There are a few places where the drawing can get by with a few dimensions. I find plastic parts basically need limited drawings, since the model provides a direct tool path to generate the mold core and cavity. And many times the parts are check by a stl model prior to final design acceptance.

But when you get to large complex hogouts of interrelating static and kinematic aircraft parts, you are not going to make stl models. A drawing in a pdf format doesn’t need the original software to view the part, can be reviewed by many eyes (I will not bore you with the many times I would be taking a break with a fellow working, and see a mistake on his drawing). So as I said before, creating a drawing now is more of a checking function. Maybe we can have a new discipline: PART AND DESIGN CHECKING. Ooops, hey didn’t we already have those guys. I will send you my final article, Norm, or you can go to www.tecnetinc.com and check to see if it is posted.

It is much easier to inspect a part with a nice concise detail paper drawing with a yellow or red marker. I think from all the specific software (undoubtedly expensive and complex) that is required in your article, drawings would be cheaper and simpler too. Of course as I said in the beginning you would have to be able to read a drawing.

Joe,
I have done drawings, and I was very good at it, long before CAD came around. I might add that I have experience doing so on military aircraft. So, I can speak from my personal experience of using the different methods of reading product design from creating and reading paper drawings to 3D solid models with value added 3D GD&T.
The "technologies" you speak of to view and read 3D solid models with intelligent value added 3D GD&T are far cheaper then the capital and maintenance cost of plotters and the paper.
Here is a real life example of through put. I worked for a company, although using CAD, plotted all the drawings, which were checked by checkers using red, yellow, and green markers. I changed that process, although using 2d drawings, the drawings remained electronic and I trained the checkers to use only what they needed to mark the drawings up using basic cad skills. The difference was a 700% increase in work throughput and far far better retieval (reuse) of the corrections to understand and learn (teach) to begin to eliminate constant errors and gain significant consistency. Doing a similar but improved process with 3D will gain similar results.
BTW are you familiar with the new PDF capability to view 3D models and the 3D annotation? Might want to look into that.

I didn’t say anything about paper ... I assume the drawings are going to be electronic generated from a 3D model... duh...and delivered as a pdf.

It is mandatory that a good drawing be provided to the outside manufacturer to completely define the part they are making. When you get one part to make, you have no idea of how it relates to other parts. Many times there are questions and you have to go back to the customer to get these questions answered. Even with a completely detailed part you may have questions. I think the drawing should be done by the original drafter, designer or engineer, except of course when you are designing little blocks with holes in them.

It seems like you are more on the design side, take some time and visit the manufacturing side to make sure you are delivering what they need.